<template>
  <view>
    <view class="scroll-view-container">
      <!-- 左侧滑动区域 -->
      <scroll-view scroll-y="true" class="left-scroll-view" :style="{height: wh + 'px'}">
        <block v-for="(item, i) in cateList" :key="i">
          <view :class="['left-scroll-view-item', i === active ? 'active' : '']" @click="activeChanged(i)">
            {{item.cat_name}}
          </view>
        </block>
      </scroll-view>
      <!-- 右侧滑动区域 -->
      <scroll-view scroll-y="true" class="right-scroll-view" :style="{height: wh + 'px'}" :scroll-top="scrollTop">
        <view class="cate-lv2" v-for="(item2, i2) in cateLevel2" :key="i2">
          <view class="cate-lv2-title">
            / {{item2.cat_name}} /
          </view>
          <!-- 动态渲染三级分类的列表数据 -->
          <view class="cate-lv3-list">
            <!-- 三级分类的item项 -->
            <view class="cate-lv3-item" v-for="(item3, i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
              <image :src="item3.cat_icon" mode=""></image>
              <text>{{ item3.cat_name }}</text>
            </view>
          </view>
        </view>
      </scroll-view>
    </view>
  </view>
</template>

<script>
  export default {
    data() {
      return {
        // wh当前设备可用高度
        wh: 0,
        cateList: [],
        active: 0,
        // 二级分类列表
        cateLevel2: [],
        scrollTop: 0
      };
    },
    onLoad() {
      const sysInfo = uni.getSystemInfoSync()
      this.wh = sysInfo.windowHeight
      this.getCateList()
    },
    methods: {
      async getCateList() {
        const {data: res} = await uni.$http.get('/api/public/v1/categories')
        if(res.meta.status !== 200) return uni.$showMsg()
        this.cateList = res.message
        // 为二级分类赋值
        this.cateLevel2 = res.message[0].children
      },
      activeChanged(i) {
        this.active = i
        // 重新为二级分类赋值
        this.cateLevel2 = this.cateList[i].children
        this.scrollTop = this.scrollTop === 0 ? 1 : 0
      },
      gotoGoodsList(item) {
        uni.navigateTo({
          url: '/subpkg/goods_list/goods_list?cid=' + item.cat_id
        })
      }
    }
  }
</script>

<style lang="scss">
  .scroll-view-container {
    display: flex;

    .left-scroll-view {
      width: 120px;
      .left-scroll-view-item {
        background-color: #F7F7F7;
        line-height: 60px;
        text-align: center;
        font-size: 12px;
        &.active {
          background-color: #fff;
          position: relative;
          &::before {
            content: '';
            width: 3px;
            height: 30px;
            background-color: #C00000;
            position: absolute;
            top: 50%;
            left: 0;
            transform: translateY(-50%);
          }
        }
      }
    }
    .right-scroll-view {
      background-color: #fff;
      .cate-lv2 {
        .cate-lv2-title {
          font-size: 12px;
          font-weight: bold;
          text-align: center;
          padding: 15px 0;
        }
        .cate-lv3-list {
          display: flex;
          flex-wrap: wrap;
          .cate-lv3-item {
            width: 33.3%;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            margin-bottom: 10px;
            image {
              width: 60px;
              height: 60px;
            }
            text {
              font-size: 12px;
            }
          }
        }
      }
    }
  }
</style>
